Other facts from our historical weather data: When is winter in Rena? The coldest season / winter is in the following months: January, February, November and December. Which is the warmest month in Rena? July has an average maximum temperature of 21°C (70°F) and is the warmest month of the year. Which is the coldest month in Rena? The coldest month is January with an average maximum temperature of -3°C (27°F). Which is the wettest month in Rena? August tops the wettest month list with 118mm (4.6 in) of rainfall. Which is the driest month in Rena? March is the driest month with 51mm (2 in) of precipitation. Which is the sunniest month in Rena? June is the sunniest month with an average of 243 hours of sunshine. No idea where to travel to this year? We have a tool that recommends destinations based on your ideal conditions. Find out where to go with our weather planner.